Generic Name: cephalexin (sef a LEX in)
Brand Name: Keflex, Panixine
What is cephalexin?
Cephalexin is in a group of drugs called cephalosporin antibiotics. Cephalexin fights bacteria in the body.
Cephalexin is used to treat infections caused by bacteria, including upper respiratory infections, ear infections, skin infections, and urinary tract infections.
Cephalexin may also be used for other purposes not listed in this medication guide.
What is the most important information I should know about cephalexin?
Do not use this medication if you are allergic to cephalexin, or to similar antibiotics, such as Ceclor, Ceftin, Cefzil, Duricef, Fortaz, Omnicef, Spectracef, Suprax, and others.
Before using cephalexin, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have kidney or liver disease, a stomach or intestinal disorder such as colitis, diabetes, or if you are malnourished.
Take this medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Cephalexin will not treat a viral infection such as the common cold or flu.
What should I discuss with my healthcare provider before taking cephalexin?
Do not use this medication if you are allergic to cephalexin, or to other cephalosporin antibiotics, such as:
ceftazidime (Fortaz); or
Before using cephalexin, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have:
a stomach or intestinal disorder such as colitis;
if you are malnourished.
If you have any of these conditions, you may need a dose adjustment or special tests to safely take cephalexin.
The oral suspension (liquid) form of cephalexin may contain sugar. This may affect you if you have diabetes.
FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
Cephalexin can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
How should I take cephalexin?
Take the medication exactly as it was prescribed for you. Do not use the medication in larger amounts, or use it for longer than recommended by your doctor. Follow the instructions on your prescription label.
Take cephalexin with a full glass of water.
Dissolve the cephalexin dispersible tablet in a small amount of water, about 2 teaspoonfuls. Stir this mixture and drink all of it right away. To make sure you get the entire dose, add a little more water to the same glass, swirl gently and drink right away. Do not swallow or chew a dispersible tablet.
Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
Take cephalexin for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Cephalexin will not treat a viral infection such as the common cold or flu.
This medication can cause you to have unusual results with certain medical tests. Tell any doctor who treats you that you are using cephalexin.
Store the tablets and capsules at room temperature away from moisture and heat.
Store the liquid medicine in the refrigerator. Throw away any unused medication after 14 days.
What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine.
Overdose symptoms may include nausea, vomiting, stomach pain, diarrhea, and blood in your urine.
What should I avoid while taking cephalexin?
Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.
Cephalexin side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
diarrhea that is watery or bloody;
fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;
pale or yellowed skin, dark colored urine, fever, confusion or weakness;
easy bruising or bleeding, unusual weakness;
confusion, agitation, hallucinations (seeing things that are not there); or
urinating less than usual or not at all.
Less serious side effects may include:
mild nausea, vomiting, diarrhea;
dizziness, tired feeling;
joint pain; or
vaginal itching or discharge.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect cephalexin?
Before using cephalexin, tell your doctor if you are using any of the following drugs:
a blood thinner such as warfarin (Coumadin);
metformin (Fortamet, Glucophage, Riomet, Actoplus, Avandamet, Metaglip); or
This list is not complete and there may be other drugs that can interact with cephalexin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
More about Keflex (cephalexin)
Related treatment guides
Where can I get more information?
- Your pharmacist can provide more information about cephalexin.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
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Copyright 1996-2012 Cerner Multum, Inc. Version: 7.04. Revision Date: 2010-12-15, 5:01:39 PM.